A komodo dragon, the world's largest species of lizard, has attacked and seriously injured a park ranger in a national park in eastern Indonesia, a park official said.

Vion Keraf, an official at PT Putri Naga Komodo, said the giant reptile, which was apparently chasing a monkey, attacked his colleague Marselinus Subanghadir on Komodo Island on Monday afternoon.

Komodo Island is part of the Komodo National Park.

''The dragon grabbed his right foot but finally he managed to escape,'' Mr Keraf said.

Komodo dragons, which can grow to three metres in length, inhabit Komodo and several nearby islands, feeding on prey that includes deer, wild boar and even water buffalo.

The ferocious carnivores typically ambush an animal, rip it apart with their large, curved and serrated teeth, and swallow chunks of flesh bigger than their own head, which they can accomplish by unhinging their jaws.

If an animal is bitten but escapes the initial attack, toxic bacteria in the dragon's saliva soon kill it through infection, and dragons then locate the carcass by their keen sense of smell.

Puri Naga Komodo is a joint venture established under the World Bank-funded Komodo Collaborative Management Initiative to work together with the park's authorities to protect its rich marine and land biodiversity and develop it as an eco-tourism destination.

Komodo, a 390-square-kilometre island in Indonesia's Lesser Sunda Archipelago, has about 2,000 inhabitants, mostly fishermen and their families, and some 1,300 komodo dragons.